"I was between (Lady) Gaga and Billy Joel, rubbing shoulders with Stevie Wonder," Terfel said, his eyes still radiating the thrill more than half a year later.

Little did those rock and pop stars know that at the wave of a spear, Terfel could have put them into eternal sleep on a craggy mountaintop, surrounded by a ring of fire, as he does to his headstrong daughter Brunnhilde in Richard Wagner's epic "Ring" cycle.

Terfel, 46 and the son of a sheep farmer from north Wales, is perhaps the most sought after singer in the world to incarnate one of the most demanding roles in opera, that of Wagner's wandering chief of the Gods Wotan.

His scheming and philandering bring about the downfall of the gods, and their palace Valhalla, in the 16-hour opera cycle's fiery conclusion.

He'll be doing it again, in October, at the Royal Opera House in Covent Garden, on the eve of the 2013 bicentenary celebration of Wagner's birth.

Terfel, who first sang the role at Covent Garden in 2007 but had to pull out of part of it due to a family emergency, and who has since sung Wotan for cheering audiences at New York's Metropolitan Opera, says this time London is going to get a performance worthy of the gods.

"I cannot wait to go on stage to do this 'Ring' in Covent Garden because I felt more comfortable in New York," he told Reuters in an interview.

"I think you can feel that I'm still working out the process, and I think this production here could be my kind of opening of the door, the lights will maybe come on ... The ingredients are there, it's just a matter of moulding and enjoying it."

In the meantime, Terfel's fans, who are legion, and anyone else looking for a heady programme of everything from Broadway showtunes to Verdi and Puccini arias can have an earful during a four-day "Brynfest" beginning on July 4 at London's Southbank Centre, as part of the music complex's Festival of the World with Mastercard celebration.

BEST OF WELSH

The festival, a celebration of all things musical, also affords an opportunity to hear the best of what the Welsh music world has to offer without ever leaving London.

While Terfel will sing Broadway showtunes with West End musical stars on the opening night, and an array of opera classics with supporting soloists the next, he will be getting a big assist from the orchestra and chorus of the Welsh National Opera.

He credits the company with providing the platform for what he considers the pinnacle of his career, his performance as Hans Sachs in a 2010 production of Wagner's "Die Meistersinger von Nurnberg".

"It was the pinnacle, yes, where a company is concerned. We were all working not individually but for the company, everything was company driven. And it was the first time I could walk into an opera house and speak Welsh with 60 percent of the cast," he said.

What is it about Wales, which in some ways never recovered from the closure of its coalmines and steel factories and has pockets of some of the most severe poverty in Great Britain, that produces great singers?

The usual answer is that colliery choirs were a fertile breeding and testing ground for young voices, but in Terfel's case it may be that his childhood mania for sports drove him to win singing competition after singing competition, to use the prize money to buy sports gear.

"It's like Dylan Thomas said, thank God we're a musical nation. I carry a certain ambassadorial role, which is quite interesting in a way because I've been given the Commander of the British Empire, I've been given the queen's medal for music, and I'm thinking, 'Look, I'm a farmer's son from north Wales, this doesn't fit into the grand scheme of how I planned out my life.'

"My life was going to be very simple, I was going to be either a sports commentator or a fireman."

Recognition at an early age that Terfel had an exceptional voice channelled him instead to London's Guildhall School of Music and Drama, where he graduated in 1989, and within three years he had made his Royal Opera House debut as Masetto in Mozart's "Don Giovanni".

By his own admission, Terfel, possibly in keeping with the rebellious Welsh character, was headstrong and even a bit of a know-it-all, but he learned quickly.

"I was horribly naive in the beginning and would quarrel at the drop of a hat just to get my points over, whereas a year or two later, having seen these wonderful people like Sir Thomas Allen, Ferruccio Furlanetto, Thomas Hampson, Placido Domingo, I said to myself, 'Hey, calm down, think about what you're going to say, think about what you're going to do and just be very grateful for the very fortunate bucket that somebody's dropped over your head'."

("Brynfest" runs at Southbank Centre July 4-7 www.southbankcentre.co.uk) (Editing by Mike Collett-White)

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